slaggywelder
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| posted on 20/7/05 at 06:42 PM |
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Penetration problem
I knew this title would cause some interest.
Seriously, I started welding practice tonight (enrolled on a course which starts in September), I don’t seem to be getting good penetration, why do I
know this well after welding chassis spec bars in a T shape I could pull them apart.
Using a MigMate 105 Turbo on high setting and not too fast feed, any help (I know the first lot will be get a better Mig) would be gratefully
received.
Mark
Why, I'd horse-whip you if I had a horse.
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stevebubs
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| posted on 20/7/05 at 06:50 PM |
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May need to go slower or raise the wire feed?
Any pics?
[Edited on 20/7/05 by stevebubs]
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slaggywelder
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| posted on 20/7/05 at 07:44 PM |
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No pics, sorry,
I tried to slow down, but it seems as if the weld sits higher on top of the metalwork (like a worm), even if I try I cannot burn a hole through, amps
are as high as they can go.
Have been given industrial CO2 so good gas (15 - 17 lpm).
I am only using the thinner gauge wire and thought I shoud try the next??
Mark
Why, I'd horse-whip you if I had a horse.
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Lotusmark2
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| posted on 20/7/05 at 07:48 PM |
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I would slow the wire feed to put more heat into the metal as you can then move slower as the wire will not "worm" on top
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JoelP
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| posted on 20/7/05 at 07:49 PM |
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what wall thickness are you welding up? it must be a really weak welder if it cant blast holes in 16gauge. Saying that, 105 amps is the bottom of the
range to be honest...
If everything is on full power, i dont know what to recommend myself - maybe try preheating the metal? And maybe lower the gas output, as it will
slightly cool the pool. Obviously make sure you are out of the wind 
Beware! Bourettes is binfectious.
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jambojeef
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| posted on 20/7/05 at 08:08 PM |
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Are you running the weld in a straight line or weavng across the join?
I tend to do little crescent moon shapes across the join or little circles to stir the pool a bit.
Not always possible if the material youre welding is thin or the wire feed speed is high but makes for a stronger weld.
Geoff
 
Rescued attachment welding.JPG
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cassidym
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| posted on 20/7/05 at 08:56 PM |
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Surely 105 Amps should be good enough for 16 Gauge? I reckon you should be able to get good penetration at about 70-80 amps - I've Tigged 16
Gauge at 40 Amps and still had 100% penetration and fusion.
Do you push or pull your gun? Pushing is better coz your arc is always preheating the metal in front. With pull you may simply pile metal on top of
the existing weld which can lead to weak penetration.
Are you sure your MIG is'nt setup for gasless welding?
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slaggywelder
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 posted on 20/7/05 at 10:46 PM |
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Right,
tried a few suggestions and I'm starting to get there, what's helping so far:
1. Slowing down more - both wire and my speed.
2. Pushing not pulling.
3. Reducing gas flow.
I think I may end up upgrading the welder, but will wait for the course first  .
Thanks for the advice and keep it coming
Mark
Why, I'd horse-whip you if I had a horse.
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JAG
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| posted on 21/7/05 at 09:21 AM |
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Check the earth connection.
Make sure it's a good tight connection to a large area of clean metal.
Justin
Who is this super hero? Sarge? ...No.
Rosemary, the telephone operator? ...No.
Penry, the mild-mannered janitor? ...Could be!
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NS Dev
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| posted on 21/7/05 at 10:20 AM |
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the real secret to mig, and one that despite being told, one still has to learn by practise, is to GO SLOW! (I had to learn this anyway)
Start welding a bead on a piece of scrap, then carry on with one hand on the torch while very gently turning the wire feed down with the other hand.
Do this until the arc starts to get erratic, then turn it up a touch from there.
Then start a new bead with your "main" hand on the torch trigger and your "other" hand steadying the shroud. This is how I
always weld, nice and controllable. You can (hopefully) now weld slowly enough that you can watch the metal melting around the arc, and move forward
at a speed dicated by the molten weld, not by the trail of metal being left on the surface.
SLOW is the key to proper mig welding, I would estimate that when welding 1.6mm thick steel I travel at roughly 1 inch per 4 to 5 seconds of welding,
not including starts or stops. (and that's with a big industrial mig, power is not the limiting factor!)
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slaggywelder
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| posted on 21/7/05 at 11:17 AM |
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Got it at last, weld almost melting through and flat (includes burning a hole through at ease if I want), what I learned so far:
1. Going slowwwwwwer.
2. Wire speed slower than I thought.
3. Better earth.
4. Lower CO2 (about 10 - 12 lpm)
4. Changed to .8 wire (????).
5. Checked the setting switches, I was setting them wrong and on very low amps rather than medium / high (ooooopppppps).
It will take much more practice and evening classes and then a welding we will go.
Mark
Why, I'd horse-whip you if I had a horse.
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NS Dev
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| posted on 21/7/05 at 12:29 PM |
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The ?????? after 0.8 mm wire?
You are quite right, best to use this wire for everything, I find (well, everything of the size that you will be welding in an average car build
anyway!)
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slaggywelder
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| posted on 21/7/05 at 08:38 PM |
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Yes, I put ?? as I'm new to Mig welding and it seemed to make a massive difference once I changed over.
Live and learn, eh!
Mark
Why, I'd horse-whip you if I had a horse.
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cassidym
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| posted on 21/7/05 at 08:54 PM |
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Delighted to hear that you're making progress. Keep it up.
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johnjulie
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| posted on 12/8/05 at 06:44 PM |
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Don't start on the serious stuff until you've started the course, you'll be amazed what you can learn in a short time.
Welding the chassis is all about penetration! It may look OK on the surface, but what you can't see is the important part! You'll see what
I mean when you do your test pieces.
Good fun, I've just finished my second year.
Don't rush!!!
Cheers John
JFDI
"Just F*****G Do It"
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